DR
AFT
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DRAFT
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D
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UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
246 of 571
1.
How to read this chapter
The contents of this chapter apply to all LPC29xx parts. Note that capture pins CAP0 and
CAP1 on timer 1 are not pinned out for LPC2927/29 and LPC2921/23/25.
2.
Timer functional description
The timers can be used to measure the time between events. An interrupt can be
generated:
•
When a predetermined period has elapsed (match functionality: see section
)
•
On an external trigger (capture functionality: see section
The timer runs at a frequency derived from the input system clock by dividing it by the
prescale value. The prescale value is programmed by writing to the PR register.
UM10316
Chapter 17: LPC29xx timer 0/1/2/3
Rev. 00.06 — 17 December 2008
User manual
Fig 61. Timer architecture
Timer
Interrupt
System
Clock
PRESCALE
VALUE
PRESCALE
COUNTER
TIMER
COUNTER
=
CAPTURE
VALUE[x]
Capture
Event[x]
MATCH
VALUE[x]